In-Flight Reboot? 594
steelem writes "The Washington Post is running a story about how the F-22 Raptor's software requires in-flight reboots. Apparently the 2 million line software project is 93% done. Knowing most projects I've been on, it'll stay that way for another few years."
Hah (Score:5, Funny)
Re:Hah (Score:2, Funny)
Re:Hah (Score:5, Funny)
Better him than Clippy. Which would you rather hear? "Peanuts, peanuts, peanuts!" or "It looks like you're barfing! Would you like some tips on ways to hold your bag?"
Re:Hah (Score:4, Funny)
Re:Hah (Score:2)
Re:Hah (Score:5, Insightful)
Recorded radio chatter of the future (Score:3, Funny)
Luke: Use the Force! Read the Source!
Re:Recorded radio chatter of the future (Score:3, Informative)
Re:Hah (Score:5, Funny)
Is this really Slashdot? :-)
Re:Hah (Score:4, Funny)
Its Major Panic, BTW. Here are some other popular ones:
Re:Hah (Score:3, Informative)
Yeah, I know, if I have to explain a joke, it's not funny. Oh well...
Re:Hah (Score:5, Funny)
LinuxBIOS in flight computers (Score:4, Interesting)
Nasa has an interesting project called FlightLinux [nasa.gov] specifically geared for this sort of application. Unfortunately, they have yet to release code (export restrictions), but they supposedly use LinuxBIOS for their system.
Of course, having software that never crashes (no pun intended) would be best, but it never hurts to have a system that can boot up in just a couple seconds anyway.
Re:LinuxBIOS in flight computers (Score:5, Insightful)
What makes you think that it takes 36 seconds to reboot their systems? That's an average time spent per flight -- we don't know how many times the systems are crashing per flight.
Also note that this covers all their computer systems, not just the actual flight control. Some systems are obviously more important than others; it probably doesn't matter if the target identification system fails for a few seconds.
Re:LinuxBIOS in flight computers (Score:5, Insightful)
Re:LinuxBIOS in flight computers (Score:5, Insightful)
Re:LinuxBIOS in flight computers (Score:5, Insightful)
Re:LinuxBIOS in flight computers (Score:5, Funny)
Sure, it's considered unsportmanlike to shoot someone with the ";)
-l
Re:LinuxBIOS in flight computers (Score:5, Insightful)
Re:LinuxBIOS in flight computers (Score:3, Insightful)
Yeah, 36 seconds a flight. Considering that most of the programming and everything is probably kept in solid state memory, a reboot maybe takes a second or two at most.
The language used for all of this is ADA, which is one devious language to program in. Everything requires exception handling, and every exception needs to be handled. The 2 million lines of code is surprising, not because it seems like a lot, but because it seems like so little.
I'm quite sure that every computerized portion of the aircr
Rickety Planes (Score:3, Insightful)
Osprey? Harrier? And how many others?
-cp- (My .sig is rebooting)
Re: LinuxBIOS in flight computers (Score:3, Informative)
> The language used for all of this is ADA, which is one devious language to program in.
Actually, I find Ada [sic] quite elegant to program in.
> Everything requires exception handling, and every exception needs to be handled.
Actually exception handlers are optional. But in avionics you probably do want to handle exceptions, regardless of which language you're using.
> The 2 million lines of code is surprising, not because it seems like a lot, but because it seems like so little.
Ada is somew
Re:LinuxBIOS in flight computers (Score:4, Insightful)
That means running the program and getting all necessary information from the hardware so that pilots can make decisions from it.
The BIOS is insignificant in this case.
Re:LinuxBIOS in flight computers (Score:5, Informative)
AFAIK, civilian flight systems are three times redundant. Written by three different isolated teams in three different programming paradigms, from three different cultures to avoid similar faults due to "contamination" by other teams, or simlar faults due to similar paradigms.
(Airbus 340 (3M LOC), Boeing 777 are said to have employed such techniques)
And IRC, they don't fly with at least two redundant fully functional systems.
It makes me wonder why the military has less stringent requirements.
Re:LinuxBIOS in flight computers (Score:3, Insightful)
There is a world of diffeence between a civilian plane which only has to fly from point A to B and the F/A-22. The F/A-22 is the most advance fighter jet in the world and can literally do things that no other plane can do. There is no way they can develope three separate software suits for a system this complex. But trust me, there is plenty of redundancy built in. Besides, the F/A-22 hasn't finished testing yet, it is not a finish
Re:LinuxBIOS in flight computers (Score:3, Insightful)
Hopefully they will cut back on a few of those airplanes and put some money into our school systems. 5 planes = 1 Billion dollars! And one of the current stealth fighters lost it's tail after air show.
I guess it's tought to keep to a budget when you can p
Re:LinuxBIOS in flight computers (Score:4, Interesting)
Re:Faulty specs (Score:3, Interesting)
This individual claimed that most of the mishaps she was aware of that were attributed to software were in fact due to faulty syst
Re:LinuxBIOS in flight computers (Score:3, Funny)
Re:LinuxBIOS in flight computers (Score:5, Informative)
Re:LinuxBIOS in flight computers (Score:2)
Re:LinuxBIOS in flight computers (Score:4, Insightful)
Granted, some things (ejector seats, cupholders, maybe even bomb-dropping aparatus) don't need computer control, but all those wing flaps and engines, etc. do, at least in a vehicle this complex.
Re:LinuxBIOS in flight computers (Score:5, Informative)
Very unstable yet very maneuverable.
What do you expect (Score:3, Interesting)
Re:What do you expect (Score:3, Funny)
the 'let's go kill people' software (Score:3, Funny)
Re: the 'let's go kill people' software (Score:5, Funny)
> the 'let's go kill people' software
Yeah, but the pilot ain't the one that it's supposed to kill.
Found more on Google. (Score:3, Informative)
The first hit on Google was this [slashdot.org] interesting take on the story.
Editors, upon submission... (Score:4, Insightful)
Likewise, when viewing for submission, check the same search, so that you can see what the use saw
BTW, this is not really a problem with just
Re: Editors, upon submission... (Score:4, Interesting)
> Please consider having Slashdot do a quick search, esp in the last 2-3 weeks. Even if this is done at the submittor level, then they could avoid this. I have no doubt that most submittors would prefer to avoid this.
Au contraire, I would guess that every time a story hits Slashdot about 9000 clowns immediately submit it again in hopes of duping the editors into a dupe.
Why reboot systems at all? (Score:5, Interesting)
Re:Why reboot systems at all? (Score:2)
Re:Why reboot systems at all? (Score:4, Informative)
There are several redundant systems. Let's say for example that your FLCC has 3 identical systems. If one fails, the other two take over until the watchdog timer kicks in and restarts the third (in the case of a software fault).
Anything that is rated for piloted flight is this way, especially fly-by-wire systems or other mission critical components.
This claim is not surprising at all, since it happens all the time.
Re:Why reboot systems at all? (Score:4, Informative)
Apollo 11 (Score:5, Interesting)
You can read more here [nasa.gov].
In flight Clippy (Score:5, Funny)
Re:In flight Clippy (Score:5, Funny)
Re:In flight Clippy (Score:5, Funny)
F-22 Raptor has encountered a problem and needs to close. We are sorry for the inconvenience. If you were in the middle of something, the information you were working on might be lost. Please tell Microsoft about this problem.
Re:In flight Clippy (Score:5, Funny)
- Get help with dying
- I'll die on my own thankyou.
Re:In flight Clippy (Score:3, Funny)
Quantum Gate (Score:3, Informative)
The "sequel that never happened" happened around 1995 and was called The Vortex: Quantum [adventurecollective.com]
Too easy... (Score:5, Funny)
Redefines 3-finger-salute (Score:5, Funny)
Why is this a big deal? (Score:5, Interesting)
Flight control software has been rebootable on the fly since the earliest days of the space program.
Re:Why is this a big deal? (Score:5, Informative)
The sensor fusion software's task is to combine the data from all of the various sources (radar, RWR, multiple datalinks etc.) and redistribute it among the systems that could benefit from it. For example, a target detected by radar would show also up on the Horizontal Situational Display, and would also be re-transmitted via datalink to JSTARS and/or AWACS and any other datalink-capable aircraft. In addition, contact information can correlated for maximum accuracy. A target's radar emissions could be detected by the Radar Warning Receiver, and that information could then be used by the radar for Non Cooperative Target Recognition allowing the radar to display the type of target (though NCTR in the F/A-22 reportedly works differently from this). All of the numerous sensors on the F/A-22 have their resources and products pooled together, allowing for extremely effective target detection, tracking and ID. Sensor fusion is an incredible development in avionics and is one of the foundations of 5th generation fighter aircraft technology.
2 MILLION lines?? (Score:2)
Ejection Seat (Score:3, Interesting)
Critical software (Score:5, Funny)
Man, I need to get a new job.
Remarkably frank ... (Score:4, Insightful)
Re:Remarkably frank ... (Score:2, Insightful)
So, what kind of talk do you expect? The kind of talk that says "let's go sing happy Barney songs around the campfire with people who have been born and bred to hate us with every fibre in their being"? Get real. In my army, I want my solders to go out and kill the fucking enemy. And don't come home until he's dead.
Re:Remarkably frank ... (Score:3, Interesting)
What disturbs me too is slashdot reporting. The article wasn't "about" the system needing reboots in flight, that was just one thing mentioned. The article was "about" a piece of military
Re:Remarkably frank ... (Score:5, Funny)
Re:Remarkably frank ... (Score:3, Funny)
Considering the context, maybe he's worried that they're referring to the _pilots_ of these planes?
Re:Remarkably frank ... (Score:4, Insightful)
thats too bad, because it somewhat indicates you are uncomfortable with reality.
I pay a lot of tax money every year to guarantee that the united states has a highly effective group of people who only exist for the purpose of killing.
I fully support killing.
I am glad that I pay my government to refine the process of killing, to make it more efficient, and to have major universities dedicated to the art and science of efficient killing.
Without killing, some disagreements just cant be settled. Im glad someone is willing to do the killing for me, so every disagreement doesn't ruin my life. I'm glad that i have the option to let someone else stick up for my interests in these disagreements that can only be settled with killing. I'm glad that the killers i dont like don't get to roll over me according to their whims.
I support killing.
Re:Remarkably frank ... (Score:3, Insightful)
And by "our civilization" I don't mean the "kill 'em all" hicks that have suddenly made a comeback in the US. I'm talking about human civilization as a whole --- the thing that seperates us from mere animals.
I've got an ant farm you just have got to see. :)
Seriously, though, I'm all for respecting life, and I don't buy into this basic fact that sometimes you have to kill somebody. I think there's a better way. Besides that, I think the best way to depose Saddam Hussein would have been assassination. W
Re:Remarkably frank ... (Score:3, Insightful)
Comment removed (Score:5, Insightful)
Distributed target tracking? (Score:2, Redundant)
Ooh.
Cheetokiller hybrid couch (Score:2, Funny)
Timing (Score:5, Funny)
Pilot: Got Radar Lock
Pilot: Hang on - just got to reboot. Will be ready in 36 seconds...
Yes, my young skywalker... (Score:5, Funny)
What does reboot even mean in this context? (Score:5, Insightful)
What's funny is I always thought the guys writing this sort of software were uber-coders, and never had this sort of problem. Throw those few extra hundred million dollars at the coding effort, and I just thought this sort of problem went away. It's worrying though - isn't code which ever needed to be rebooted fundamentally flawed? Can you ever really fix that sort of code, or are we just waiting for the day whenever another edge test case comes along mid-flight, and an F-22 falls out of the sky? Even one of this sort of error seems like impending doom to me.
Re:What does reboot even mean in this context? (Score:3, Informative)
This isn't a big deal (Score:5, Interesting)
This has been coming for a while (Score:5, Insightful)
Second, I have seen this coming for about 10 years now. In the 70s and 80s I worked with digital control systems. Not avionics, but similar. In those days the systems were expected to work right, every time, for years at a time. 2 years between system restarts was considered "acceptable". If a system did fail, the manufacturer was expected to get its collective butt out to the site, figure out why, and issue a (solid!) fix pronto.
In the last 5 years, I have repeatedly been on brand-new airplanes at the gate when the pilot comes on and says "we are having a little problem with the system - don't be alarmed if the lights go off" followed by what is clearly a "reboot" of the airplane! When the fsk did it become acceptable to fix problems in avionics by rebooting the airplane?
And if the system designers really think the Microsoft Rebooting Disease is an acceptable way to handle system faults, how long before one of those faults occurs in the air?
I guess I am just old and crusty, expecting life-critical systems to work to spec 100.0% of the time.
sPh
Knights of the Sky (Score:5, Funny)
I wonder if modern day pilots are going to need a way to signal their opponent that their computers are rebooting?
Myth: Gentlemen. Reality: Never saw it coming (Score:4, Insightful)
Not the first time (Score:5, Funny)
Told to me by a pilot, I can't verify via a quick google.
Must be running windows (Score:5, Funny)
[*] Land
[ok](cancel)
You must reboot your computer for the new settings to take effect...
Cool! (Score:4, Funny)
I can already imagine the cockpit layout of a Raptor... Altimeter, speedometer, non-functional IFF indicator, roll indicator, yaw indicator, pitch indicator, three displays for tactical data, fuel indicator, HUD, control, alt, delete...
At least Windows would be fitting on an aircraft... It's easier to move a mouse cursor around with a joystick then to type "shutdown -r now" with it!
Microsoft bashing (Score:5, Insightful)
Yes, you're all very droll, but the Microsoft bashing seems a little knee-jerk. It's insanely complicated to write software like this (as a few other posters have said, and I'm posting only because I have no mod points for them).
I doubt these errors are OS-based at all. Real-time systems like this are built on top of extremely well-tested embedded OSes. They reboot because they're writing pretty close to the bare metal, and mistakes are punished hard. Best practices are applied (interminable code reviews, fascist levels of regression testing, ungodly coding style standards), but not always followed, and even best practices don't always work.
I'd like to see a gradual shift to languages which enforce best practices (i.e. not C and assembly). Meantime, these pilots are pretty damn brave. But it's probably not Microsoft's fault, this time.
Welcome to F22 Raptor version 3.1 (Score:3, Funny)
A phone call to tech support... (Score:3, Funny)
Pre-recorder message: We're sorry, all circuitys are busy now. Your call is very important to us, please stay on the line until an operator is availible.
Pilot: (Over enemy territory and ready to drop payload, toggling switches like a madman) Damnit, pick up.
Tech Support Person: Hi, This is Candice, how are you today. Pilot: (Engine failure light flashing) Can you can the chatter, I'm cruising over Eastern Kreblenkistan about to die at Mach 40,000.
Candice: There's no need to be rude sir. First I'll need to confirm that you're not using a pirated copy of our software, so will you please refer to the key sticker located on your computer. Pilot: (Frustrated, going down) I can't do that, I'm sort of in a plane right now, can you just tell me how to reboot the thing.
Candice: I'm sorry sir, but we can't be responsible for the failures of pirated software... (transmission ends, big fiery explosion)
Cancel this project now (Score:4, Interesting)
Why? It's a problem program. It's been plagued with an abundance of serious unforseen engineering problems from the very beginning. This is just the latest one made public. Past problems have included repeated instances of various parts of the fuesalage (especially some wing and tailparts) cracking. Cost overruns have become endemic. When the ATF program (Advanced Tactical Fighter) was first launched in the mid-80's to find a successor to the legendary F-15 Eagle, the Air Force set a goal of a flyaway cost of no more than 35 million per copy. The cost is now up 200 million a copy, and before it goes into production, the F-22 might cost a quarter of a billion dollars FOR A SINGLE FIGHTER. No matter how rich a nation is, no Air Force in the world can afford to buy such fighters in effective quantities. Not even other Stealth projects have spiraled this far out of control. The F-117 NightHawk stealth fighter (really more of a small bomber), with a small inefficient production run of 64 aircraft, topped out at 61 million per copy.
Granted, not all of the cost overrun problems are the fault of the Air Force or of Lockheed Martin. Congress keeps screwing around with the production schedule, and reducing the total buy, which drives up the cost per aircraft. But Congress has done so in large part for three main reasons:
1- They ask "Do we really need this, or can upgraded F-15's do the job?" This is a valid question as no other nation, friend or foe, has an aircraft that equals the Eagle, save for Russia's SU-27 series of fighters. These have been produced in such small quantities that Congress still debates the need for an Eagle replacement.
2- The number and seriousness of technical problems has made Congress reluctant to commit to the project fully. This crosses party lines, as in the past few years, several powerful Republicans have tried to kill the program on the grounds that the Raptor is a lemon. Democrats seeking money for non-defense programs have joined them.
3- There are serious doubts emerging that the Raptor's massive complexity can ever truly be managed in an efficient manner. There are concerns that, even if the aircraft becomes operational and initial bugs are worked out, the aircraft will be unreliable, becoming what the Air Force calls a "Hangar Queen"; it looks pretty on the floor, but if it can't go up in the air regularly, how good is it? The Air Force has had aircraft before that they REALLY wanted, but turned out to be so expensive and maintenance intensive that they had to be retired early. And excellent example is the B-58 Hustler supersonic bomber, which had impressive performance...when it wasn't broken down. It was retired after only 10 years of frontline service.
Re:Cancel this project now (Score:4, Interesting)
In other words, don't buy Raptors: buy the engineers, and let them try again, the wiser for the experience.
Gentoo F22/Java F22/FreeBSD F22 (Score:4, Funny)
Su-30 series or Quality/Quantity (Score:5, Interesting)
In pure features the Su-27 is an amazing plane. Anyone who has ever seen the Su-27 do the cobra [lucia.it] manouver or the thrust vectored Su-30MKI or Su-35 do the 360 degree Kulbit manouver can attest to what these planes can do in close air combat. These are extreme manouvers that western planes cannot do for the simple reason that the engines in western planes receive no air at such high angles of attack and therefore often flame-out or stall. Not only this but the newer radars on the Su-30s and missiles are longer ranging than just about anything the west has with the exception of the F-14's AIM-54 Phoenix. As for stealth, newer Su-30's are coated with radar absorbant paint which reduce the advantages that a dedicated stealth fighter such as the F-22 would have in BVR combat.
In the hands of a good pilot I very much doubt that the Su-30 would automatically lose in combat. That however is the crux of the matter: Pilot training.
This has always been something that has been much better in the west with advanced simulators, top gun style combat training and long hours of aircraft experience. It is and has been a fallacy to believe that more modern high tech will always win the battle. It is almost always the quality of the pilots that decided the battle.
There is a good example of an air combat situation atht happened in the first gulf war. The only western plane to be shot down in air combat was an F-18 on an attack mission that was intercepted by an obviously experienced Iraqi Mig-25 pilot. The Mig-25 was already obsolete then in terms of technology but the sheer speed of the plane (Mach 2.8+) is unmatched by any other fighter. The Mig-25 went on after shooting down the F-18 to buzz an EF-111 raven that was providing ECM for the mission causing the raven to have to manouver to avoid the incoming missiles and drop back from the attack mission which was then unprotected by ECM and subsequently another F-18 was shot down by a SAM. No less than two F-15's and two F-16's all attempted to intercept the Mig-25, two of them firing missiles, but the Mig-25 used it's tremendous speed advantage to easily avoid the interceptors and reach its base.
This shows what a good plane , not necesserally the utterly most modern, can do in the hands of a good pilot. IMO the F-22 is an overexpensive white elephant.
Re:Su-30 series or Quality/Quantity (Score:3, Informative)
Um...bullshit.
The F-15 had to perform the cobra in acceptance testing. It's covered in 4.2 of Mil Std 1787. There are other aircraft that can also perform the maneuver. The cobra is nothing more than a pitch overshoot in response to a "stick snatch." It's p
Re:Su-30 series or Quality/Quantity (Score:4, Informative)
The Mig-25 borders on a desparation weapon. It was designed specifically to counter high altitude bombers and spy planes that the United States routinely flew over Soviet airspace. In that it failed. It's fairly clear today that a Mig-25 could not sustain the speed or attain the altitude necessary to attack an SR-71.
The Soviet Union pawned off various models of the Mig-25 to the third world. Iraq had probably 15 Mig-25s at the start of the Gulf War (the first), of which perhaps 7 were operational.
The shootdown happened because the Mig was misidentified multiple times as it flew past an American strike package. Had it been identified, it would have been killed. The shootdown was more the result of tactics than technology. That Mig pilot was both brave and lucky.
The Mig was not moving at Mach 2.8. A Mig-25 can only do this at high altitude (70K+) and only for a short time. The shootdown happened between 25-30K, where the F-18's were operating. Flying at almost Mach 3 destroys the engines of a Mig-25. This isn't a problem if you're goal is to hit one high-value, high-altitude target and glide back to base. It does matter if you intend to engage in sustained warfare.
In 1976, a Soviet defector landed a 1976-built Mig-25 in Japan. A few interesting things [wvi.com] were learned; with a full load of weapons and fuel a Mig-25 can handle only slightly more than 2Gs of force. At it's best it can handle about 5gs. This is no dog fighter. An F-4 can do better, much less any modern aircraft.
Re:Su-30 series or Quality/Quantity (Score:3, Informative)
For the record, I misquoted the story. Here's a link [lucia.it].
I quote: "Gulf War Experience -
Did you know that a MiG-25PD recorded the only Iraqi air-to-air kill of
Fault-tolerant/robust system engineering (Score:5, Insightful)
Rather than the monolithic system which we all secretly love (which allegedly produces Blue Screens of Death when things go squiffy, although my own XP Home system has been thundering on with nary a problem for quite a while now), you build systems which can tolerate components restarting themselves. I don't care if you're RMS writing the purest code with GNU/Ada for the EFF Air Force, you're not going to write something that will never fail. Better to design and build an overall system which can tolerate minor interruptions, especially if you are going to be flying into a war zone.
In any case (I worked on some of the stuff on the fringes of the F22 program a long long time ago), there are a bunch of computers in the air vehicle; it's an airborne network. Saying "oh my god, I can't believe the plane is rebooting" is dissingenuous.(aside from the many Windows jokes). It's akin to "I had to power-cycle the printer twice today -- I can't believe the network stayed up for the 35 seconds it took the Lexmark to come back to life!".
Rebooting a subsystem computer works quite well in robotics too, which further leads into the concept of many small robots rather than one large beast screaming "Danger Will Robinson".
Nothing new here (Score:4, Interesting)
This was 1980.
It got fixed.
-dB
Press conferences of the future... (Score:3, Funny)
"The State Dept. would like to report that it is doing its best to retrieve Lt. Col. John Bowers from enemy territory right now. Lt. Col. Bowers due to system failure, was forced to Ctrl-Alt-Del out over southern Liberia earlier this week."
Re:I wonder... (Score:2)
Re:I wonder... (Score:3, Funny)
Re:It may be normal... (Score:5, Insightful)
I'm curious -- do you do development? Have you ever worked on a 2 million line program? No offense, but anyone who uses the word "merely" in a paragraph like that strikes me as someone with a tenuous grip on reality.
I am a senior engineer at a very big company. Applications I have written are in use by literally millions of people. And I'm scared stiff by the idea of writing the kind of software that powers the F-22. Software of this scale is the single most complicated project humanity has ever undertaken, and to belittle the efforts of the engineers involved by suggesting that they don't know what they're doing or aren't following responsible development guidelines shows a serious lack of understanding. I promise you, the software on the F-22 has been subjected to more rigorous QA than anything you or I have ever touched, but that still doesn't make it easy.
Humans aren't perfect, and as long as that continues to be the case, writing a multi-million line chunk of software will always be a ridiculously expensive and difficult proposition with no guarantee of success.
Re:It may be normal... (Score:5, Insightful)
I think where people get thrown is that they see houses and cars and bridges and think, "If we can build those, why can't we build software? Programmers must be lazy"
Well, is every 2x4 in a house the exact same length? Are all the boards perfectly flush? A crooked door in a house will usually cause no problems, but the equivalent in a piece of software can cause a crash. Even computer hardware is never perfect. Does every 2.0 GHz processor run at EXACTLY 2.0 GHz? Not even close, but they are good enough. The problem with software is that it needs to be perfect to be perfect, and people aren't perfect.
The beauty of the F-22 system is that the developers realize this, and they designed the system knowing there would be flaws and that the software would crash. When some of the software crashes, the jet keeps right on going, which is the sign of ultimate stability.
Re:WHAT?!?!?! (Score:4, Insightful)
With ten thousand workers to help, a government that doesn't give a crap about death tolls or reasonable working conditions, and enough funding to bankrupt an empire, I'm sure I could manage.
The pyramids were gigantic, backbreaking undertakings, but I maintain my stance that software is the most complicated endeavor undertaken by mankind.
Wrong (Score:4, Funny)
Re:Avionic stability? (Score:5, Informative)
The APG-77 has a terrain following mode. And the widely spread weak emissions from it are much harder to detect than those from a conventional radar.
The Martin-Baker ACES II ejection seat can save a pilot's life from zero feet of altitude (that's why it's called a "zero-zero" ejection seat- effective down to zero altitude and zero speed)